Assertion : A certain element X, forms three binary compounds with chlorine containing 59.68%,68.95% and 74.75% chlorine respectively. These data illustrate the law of multiple proportions.
Reason : According to law of multiple proportions, the relative amounts of an element combining with some fixed amount of a second element in a series of compounds are the ratios of small whole numbers.

Options

A. If both assertion and reason are true and the reason is the correct explanation of the assertion.
B. If both assertion and reason are true but reason is not the correct explanation of the assertion.
C. If assertion is true but reason is false.
D. If the assertion and reason both are false.

Explanation

To solve the question, we need to analyze both the assertion and the reason provided, and then determine if they are correct and related to each other.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
The assertion states that element X forms three binary compounds with chlorine that contain 59.68%, 68.95%, and 74.75% chlorine. We need to check if this data illustrates the law of multiple proportions.

2. **Calculating the Mass of Element X**:
For each compound, we can calculate the mass of element X by assuming a fixed mass of chlorine. Let's assume we have 100 g of each compound for simplicity:
- For the first compound (59.68% Cl):
- Mass of Cl = 59.68 g
- Mass of X = 100 g - 59.68 g = 40.32 g
- For the second compound (68.95% Cl):
- Mass of Cl = 68.95 g
- Mass of X = 100 g - 68.95 g = 31.05 g
- For the third compound (74.75% Cl):
- Mass of Cl = 74.75 g
- Mass of X = 100 g - 74.75 g = 25.25 g

3. **Finding Ratios of Masses of X**:
Now we will find the ratios of the masses of element X that combine with a fixed mass of chlorine (let's take the mass of Cl from the first compound, 59.68 g):
- For the first compound: X = 40.32 g
- For the second compound: X = 31.05 g
- For the third compound: X = 25.25 g

Now, we can express the ratios of the masses of X:
- Ratio of X in the first compound to X in the second compound:
\[ \frac{40.32}{31.05} \approx 1.30 \]
- Ratio of X in the first compound to X in the third compound:
\[ \frac{40.32}{25.25} \approx 1.60 \]

4. **Checking for Small Whole Number Ratios**:
The law of multiple proportions states that these ratios should be small whole numbers. We can simplify the ratios:
- The ratio of 1.30 can be approximated to 1.3:1, which is not a small whole number.
- The ratio of 1.60 can be approximated to 1.6:1, which is also not a small whole number.

5. **Conclusion**:
Since the ratios of the masses of element X do not yield small whole numbers, the assertion that these data illustrate the law of multiple proportions is incorrect. However, the reason provided is correct as it accurately describes the law of multiple proportions.

### Final Answer:
- **Assertion**: Incorrect
- **Reason**: Correct